161183947777 has 4 divisors (see below), whose sum is σ = 162995003460. Its totient is φ = 159372892096.

The previous prime is 161183947723. The next prime is 161183947817. The reversal of 161183947777 is 777749381161.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 82676951296 + 78506996481 = 287536^2 + 280191^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-161183947777 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161183917777) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 905527708 + ... + 905527885.

It is an arithmetic number, because the mean of its divisors is an integer number (40748750865).

Almost surely, 2^161183947777 is an apocalyptic number.

It is an amenable number.

161183947777 is a deficient number, since it is larger than the sum of its proper divisors (1811055683).

161183947777 is an equidigital number, since it uses as much as digits as its factorization.

161183947777 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1811055682.

The product of its digits is 12446784, while the sum is 61.

The spelling of 161183947777 in words is "one hundred sixty-one billion, one hundred eighty-three million, nine hundred forty-seven thousand, seven hundred seventy-seven".